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Tuesday, July 15, 2008

The Phoenix 6.2L Diesel Rebuild


My son Jens stays busy with an international transportation company, keeping their aging equipment between North Vancouver and Lillooet running: laying track, operating heavy machinery and generally making himself useful.
Ever since high school, Jens has participated in an annual silliness around here known as The Birken Ralley. The local off-road enthusiasts spend all their disposable income and sometimes more to build the toughest trucks. Then – here’s the silliness – they get together every Spring and drive out into the bush to get drunk and wreck their masterpieces. Early on in the madness, Jens recognized the superiority of the 1967 to 1972 Chevy/GMC body style. The high degree of GM part interchangeability, the simple, classic lines, the uncomplicated, before-pollution-control systems and the heavier-than-today sheet metal convinced him that the last of the line, the ‘72, represents the zenith in the development of the North American pickup truck. Over the years, he has built up quite a number of these vehicles and he has come to understand them down to the molecular level. In his work travels, he keeps his eye out and knows the location and condition of every one within a couple of hundred miles of home.

A Cherry... Flambeaux

Back in the mid-eighties, a particularly cherry ’72 “heavy half” became available and Jens and his brother, Ole – a talented and certified Chevy mechanic as well – promised to build it up for me if I bought it.

The original 1972 pickup: proof that some treasures lie hidden behind rough facades – for those, like Peter Legere, with the eyes to see them.


Ole rented a detached, double carport in an older section of town and I helped him enclose it, insulate it and install some doors and heavy-duty wiring for a compressor. We disassembled the truck and Ole, over the period of six months or so of spare time, repaired, sanded and prepped the front clip parts, the box parts, all the hinges and latches and window hardware etc and rebuilt the cab, repairing the floor and replacing the cab corners and rocker panels. We had the cab and chassis towed to a local body shop to have the interior of the cab painted. While the truck was at the body shop, Ole stacked all the parts out of the way at the back of the shop and moved a demolition derby car in and put it up on blocks. He was sitting on the hood burning holes for the straight exhaust pipes when he started to get uncomfortably hot. Shutting off the torch, he jumped down onto the floor and saw that a pan of oil he had left under the engine was burning merrily. He grabbed a fire extinguisher and aimed it under the car at the fire. The force of the jet from the extinguisher was too much for the heat-softened sides of the plastic pan: they collapsed, spreading flaming oil across the floor of the shop. Unquenched, the growing inferno swallowed up the foam from his last extinguisher. Before long, flames burnt through the hoses of his torch that transformed, before his eyes, into a fire-breathing dragon, writhing and then darting back and forth and all around through the air, torching the tinder-dry structure and everything flammable within it. There was nothing he could do but get the hell out and find a phone to call the fire department.
By the time the firemen arrived, the building was fully engulfed in flame and the propane tanks from the heating system had begun to explode, rattling windows throughout the neighborhood. A great pall of black smoke rose into the afternoon sky. While the cab and chassis survived the fire – safe at the body shop – everything else needed for the project was lost. Our dream pickup project had come to a spectacular end. Ole lost all his tools and equipment: he has not done any body work since.

A 6.2L Diesel Work Truck

In the intervening years, Jens wheeled and dealt, wrecked and built: always setting aside the best parts for the inevitable resurrection of what we had come to call, after the fire, “The Phoenix Project”.

Parts for the Phoenix 6.2L Diesel Rebuild stacked up outside the workshop.


Since this pickup would be the workhorse hauler for my building business, I wanted it to be as economical to operate as possible. With that in mind, we had set aside a nice
283 and a propane system we had run across for it. Then, about three years ago, Jens’ father in law offered his old 1980 diesel Turbo 400 automatic pickup to us for $1,000. The original 5.7L had calved, (as they have tended to do) and he had recently replaced it with a ’82 6.2L diesel in good shape. He hadn’t driven it very long before the cab and front clip collapsed from rust. Jens assured me that the engine swap would be relatively simple and I thought, “What is the only improvement one could make to the best pickup truck ever produced? Why, a diesel automatic drivetrain, of course!” I cut the check.
It was another two-and-a half years before The Project made it to the top of the priority list, but just after Christmas 2006, Jens finally got started. We set our sights on the upcoming “Show and Shine” eight months away.
Once the rusty ’80 Chevy was dismantled, the engine and transmission pressure-washed, the cab removed from the ’72 frame and the frame washed and painted, it was time to fit the 6.2L to the older frame. Jens removed the engine frame brace from the ’72 frame. He then bolted the ’80 frame brace to the diesel engine mounts and lowered the engine-tranny assembly into place using the original transmission mount on the ‘72 frame. Two of the holes in the frame lined up perfectly with the ’80 engine mount bracket; he had to drill two more in the top frame flanges and two in the bottom flanges in order to bolt the drive assembly into place. He replaced the universal joint behind the transmission output yoke with a half-ton to three-quarter-ton adapter – available in most auto parts stores – and the ’72 drive shaft connected up to the existing 3.07 rear end without modification.

The 6.2L diesel mounted to the ‘72 chassis with minimal adaptation. 
The wiring harness for the ‘72 required only slight adaptation as well.

After the firewall and the underside of the cab was cleaned and painted, the cab was bolted back on and the stock ‘72 brake booster replaced with the ’80 Hydra-Boost unit, which fit the original ’72 studs. Jens then modified the ’72 brake pedal by welding a simple plate on the forward edge, thus moving the pushrod mount up and forward to meet with the new pushrod mount position from the Hydra-Boost. He replaced the ’72 steering box to the ’80 so that the O-ring fittings would match up.

Two of the holes in the frame lined up perfectly with the ’80 engine mount bracket;he had to drill two more in the top frame flanges and two in the bottom flanges in order to bolt the drive assembly into place.

By this time I could foresee the end of the project and I was anxious to upgrade my involvement from mere check-writer to something hands-on. I am a bit more comfortable around a soldering iron than Jens is, so I helped him with some modifications to the wiring harness. Because the glow-plug controller for the new engine no longer worked, Jens decided to replace it with a momentary toggle switch, easily reachable under the dash to the left of the steering column. We also took the instrument cluster apart and mounted the glow plug indicator light in an unused bezel. While I see this as brilliantly simple replacement for a more complicated system, Jens has other standards, so I soldered some proper plugs into the “temporary” system so that the controller could be merely plugged in if and when it became available in the future.
We used the original wiring harness from the ’72 with a couple of modifications. Since the external voltage regulator from the ’72 was made obsolete – thanks to the internal regulator in the heavy-duty alternator that came with the diesel – Jens removed it. This enabled him to simply run the power lead up the firewall from the starter – instead of out to the radiator support – and over the radiator to the battery, according to stock configuration. Since the resistance wire to the coil was also obsolete, Jens removed it as well and replaced it with the heavy orange wire from the donor truck harness leading to the fuel shutoff solenoid.

The side panels (top) – ready for the body shop – with the fuel-filler doors installed and the duel fuel tanks (bottom) fabricated to replace the original tank.

It was time to get the truck mobile for the move to the body shop, so a temporary radiator support and inner fenders were bolted on. Jens mounted the ’72 four-core radiator because the lower hose connection was upturned to clear the inner fender. This meant adding an external engine oil cooler and, for good measure, an external transmission cooler. We fitted a shroud from a big block ’72; all the wiring for the front clip draped over the inner fender. A plastic jug became the temporary fuel tank and the cab and chassis was now mobile and ready to go for the bodywork and paint, along with the rest of the external sheet metal.
Jens recommended an old schoolmate of his who had a reputation for good work and we delivered everything, plus a few spares for patches where necessary, to his body shop. A trip to the local scrap yard with the zip-cut yielded two fuel filler doors from a newer Chevy van for installation in the box side panels. We purchased a new after-market tailgate and included that as well; 35-year-old tailgates in good shape are hard to come by.
In the meantime, Jens gathered all the other body parts together to be cleaned and painted: the hinge and latch mechanisms, the inner fenders and radiator support. I spent the next few days at the sandblasting cabinet and wielding a small angle grinder with a wire wheel.

The original bed had been eaten up with rust...

The only big job left to do was the box floor. We had three old floors and some pieces to make into one. We never had any intention to build a show truck, this was to be our everyday work truck; and so, as long as the bed was solid, it would suit. We took inventory of all the floors and floor sections we had on hand and picked the bed with the best crosspieces as our starting point. Over the next couple of weeks, armed with a 4-1/2” mini-grinder, a stack of zip-cut disks and a few grinding wheels, I cut out the rotted metal and fitted patches during the day. Jens mig-welded my fittings together after he got home from work. I got pretty good at it after a while and even discovered that if your grinding wheel is just the right shape and you hold it in just the right position and apply just the right amount of pressure at just the right angle and the gods are propitious, you can set up a puddle of molten steel in front of your grinding wheel that will melt the excess bead in front – and you can shave it off flush in one pass.

Rebuilding the pickup bed... and the finished product.

The next job was the preparation of the new fuel tanks that had been fabricated locally. Jens brought home a float and sender unit for the fuel gauge and I prepared one tank for installation. Once the installation was complete, I did a mirror-image layout on the second tank, drilled the holes and temporarily mounted the tanks on the box bed for the fitting of the filler pipes.
By this time everything had come back from the body shop. Jens’ chum, Aaron, had done a bang-up job of the small panel repairs, patching the stock fuel filler hole in the cab and fitting the new fuel fill doors in the box sides. His paint job, metallic gray with a clear overcoat, was almost flawless. We installed the box sides temporarily on the bed in order to fit the fuel filler pipes, which Jens had obtained from the local auto wrecker. We had to cut notches in the bed and the inner box panels to make way for the angled filler pipes and Jens tasked me with the job of making small boxes to hide and protect the pipes which projected about two inches into the inside bottom corner of the box. With the ridges in the bed and a little step in the inside box side panel, this meant a bit of complicated metal fabricating – maybe most of a day’s work – with the tools available and my metalworking experience. Being a woodworker, I made up a couple of wooden boxes in about a half hour and fastened them through the inside box liner with 10x24 bolts, the nuts reachable through the fuel filler door. We then unbolted the fuel tanks and Jens welded in the filler pipes and all the necessary fittings.

The finished side panels, cab – with the fiery red top – and chassis begin to give us an idea of what the finished firebird will look like...

The Show-and-Shine was fast approaching, so the next few weeks were spent in feverish assembly. It was a wonderful feeling to see the project finally coming together after all the years of planning, disappointment and anticipation. The fitting of the new fuel tanks under the box bed meant that the stock fuel tank behind the seat was no longer needed, so Jens modified it into a storage bin and re-installed it. The heavy front anti-sway bar from the ’80 donor truck bolted right in, and the “Y” pipe from the diesel was split and the pieces rotated to line up with the ’72 dual exhaust. He found a very nice bench seat from a newer Chevy pickup at the local wrecking yard (which matched the burgundy paint we had picked for the roof) and fabricated some brackets for it. It ended up an inch or so higher than stock, but there is still room for hard hats below the headliner and I like the extra height for better visibility over the hood.
At the Show and Shine, we received the People’s Choice trophy for the second best pickup, beaten out by a show truck driven only on weekends.
There is still a pretty long list of stuff to be finished before this project can be deemed complete. The second battery, for instance, was installed where the windshield washer fluid tank belongs, so a place has to be found under the hood for that. We still have to locate a water temperature-sending unit which will activate the gauge and fit the threaded hole in the block and the exhaust system needs to be custom-fit. We have ordered stronger front coils to replace the original tired ones and make up for the extra weight of the diesel. I do like the cool rake, though. I don’t think the stronger coils will take it all out.
The Phoenix is fun to drive and draws compliments from passers-by wherever it is parked. Curiously enough, it seems to especially attract young women. Go figure! I took it over to the Small Boat Harbour a couple of weeks ago to photograph it. As I was idling off the dock after I had finished, there was a guy walking towards me from the shore. I saw the appreciation break over his face when he noticed that it was a restoration; and, as I approached, I watched his expression change when it dawned on him that the truck didn’t sound like it should. Then his expression changed again when he realized it was a diesel and he stopped and watched me drive by. It’s nice when somebody “gets it”.

1972 GM pickup Custom 10 Badge

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